Structural health monitoring of liquid-filled tanks: a Bayesian approach for location of acoustic emission sources

Abstract

Acoustic emission (AE) is a well-established nondestructive testing method for assessing the condition of liquid-filled tanks. Often the tank can be tested without the need for accurate location of AE sources. But sometimes, accurate location is required, such as in the case of follow-up inspections after AE has indicated a significant defect. Traditional computed location techniques that considered only the wave traveling through the shell of the tank have not proved reliable when applied to liquid-filled tanks. This because AE sensors are often responding to liquid-borne waves, that are not considered in the traditional algorithms. This paper describes an approach for locating AE sources on the wall of liquid filled tanks that includes two novel aspects: (i) the use of liquid-borne waves, and (ii) the use of a probabilistic algorithm. The proposed algorithm is developed within a Bayesian framework that considers uncertainties in the wave velocities and the time of arrival. A Markov Chain Monte Carlo is used to estimate the distribution of the AE source location. This approach was applied on a 102 inch diameter (29 000 gal) railroad tank car by estimating the source locations from pencil lead break with waveforms recorded. Results show that the proposed Bayesian approach for source location can be used to calculate the most probable region of the tank wall where the AE source is located.

Numerical approach to absolute calibration of piezoelectric acoustic emission sensors using multiphysics simulations

“…4, and then the magnitude of the force function is obtained using Eq. (7). The magnitude of dipole force is calculated as 2.258 N. The source function of PLB is represented as a point load (see in Fig.…”

“…The damage initiation is typically identified using the cumulative energy graph of AE signals [6]. The damage location is determined using the time of flight differences of sensor arrays strategically positioned on the structure [7]. However, understanding the quantitative meaning of damage, such as source mechanism from the transient AE signals, is still a challenging research problem.…”

Nonlinear updating method: a review

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